#include <bits/stdc++.h>

using namespace std;

class Solution
{
public:
    int uniquePathsWithObstacles(vector<vector<int>> &obstacleGrid)
    {
        int m = obstacleGrid.size(), n = obstacleGrid[0].size();
        vector<vector<int>> dp(110, vector<int>(110, 0));
        bool flag = false;
        for (int i = 0; i < m; ++i)
        {
            if (flag)
            {
                dp[i][0] = 0;
                continue;
            }
            if (obstacleGrid[i][0])
            {
                dp[i][0] = 0;
                flag = true;
            }
            else
            {
                dp[i][0] = 1;
            }
        }
        flag = false;
        for (int i = 0; i < n; ++i)
        {
            if (flag)
            {
                dp[0][i] = 0;
                continue;
            }
            if (obstacleGrid[0][i])
            {
                dp[0][i] = 0;
                flag = true;
            }
            else
            {
                dp[0][i] = 1;
            }
        }

        for (int i = 1; i < m; ++i)
        {
            for (int j = 1; j < n; ++j)
            {
                if (obstacleGrid[i][j])
                {
                    dp[i][j] = 0;
                }
                else
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
            }
        }
        return dp[m - 1][n - 1];
    }
};